FTP 150 File Status OK vs 502 Command Not Implemented
FTP 150 (File Status OK) is a 1xx Positive Preliminary response, while 502 (Command Not Implemented) is a 5xx Permanent Negative response. 150 indicates that the file status is okay and the server is about to open the data connection for the transfer. This is the normal precursor to a file transfer. In contrast, 502 means that command not implemented. The server recognizes the command but does not support it in its current configuration.
Description
The file status is okay and the server is about to open the data connection for the transfer. This is the normal precursor to a file transfer.
When You See It
Right before a file download or upload begins, confirming the file is accessible and the data channel is being opened.
How to Fix
No fix needed — this means the transfer is about to start. If the transfer stalls after this reply, check firewall rules blocking the data connection.
Description
Command not implemented. The server recognizes the command but does not support it in its current configuration.
When You See It
When you use a valid FTP command that this particular server has not implemented, such as SITE or SMNT.
How to Fix
Use an alternative command or approach. Check the server's FEAT response or HELP output to see which commands are actually supported.
Key Differences
150 is a 1xx Positive Preliminary response, while 502 is a 5xx Permanent Negative response.
FTP 150: The file status is okay and the server is about to open the data connection for the transfer. This is the normal precursor to a file transfer.
FTP 502: Command not implemented. The server recognizes the command but does not support it in its current configuration.
You encounter 150 when right before a file download or upload begins, confirming the file is accessible and the data channel is being opened.
You encounter 502 when when you use a valid FTP command that this particular server has not implemented, such as SITE or SMNT.
When to Use Which
For 150 (File Status OK): No fix needed — this means the transfer is about to start. If the transfer stalls after this reply, check firewall rules blocking the data connection. For 502 (Command Not Implemented): Use an alternative command or approach. Check the server's FEAT response or HELP output to see which commands are actually supported.